Selected Spacewatch Near Earth Asteroids
and other notable asteroid discoveries
The following table shows some of the more interesting objects that have
been discovered by Spacewatch in recent years. The table lists the object's
designation along with its closest approach to the Sun (perihelion),
furthest distance (aphelion), and inclination of the orbit to the plane
of the ecliptic.
Perih Aphel Incl Diam Disc
Name (AU) (AU) (deg) (km) Date Remarks
--------------------------------------------------------------------------------
1989 UP 0.98 2.7 3.9 0.3 10/27/89 perihelion at Earth orbit
1990 SS 0.89 2.5 19.4 0.6 09/25/90 Apollo
1990 VA 0.71 1.3 14.1 0.6 11/09/90 Aten; (5590) perihelion at Venus orbit
1991 BA 0.71 3.8 2.0 0.008 01/18/91 Apollo
1991 VG 0.97 1.1 0.3 0.014 11/06/91 Apollo
1992 AD 8.69 32.0 24.7 160 01/09/92 Centaur(5145)
1993 HA2 11.2 38.5 16.7 58 04/26/93 Centaur
1993 KA2 0.50 4.0 3.2 0.007 05/21/93 Apollo
1994 GL 0.34 1.0 3.7 0.08 04/07/94 Aten
1994 XM1 0.90 3.1 5.6 0.010 11/09/94 Apollo
1995 CR 0.12 1.7 4.1 0.16 02/03/95 Aten
1995 GO 6.69 36.9 17.3 58 04/04/95 Centaur
1996 AJ1 0.31 2.3 2.4 0.3 01/12/96 Apollo
1996 XB27 1.13 1.26 2.4 0.15 12/12/96 Amor; low eccentricity!
1997 CD17 0.97 1.28 15.1 0.015 02/09/97 Apollo; small, low eccentricity
1997 CU26 12.9 18.9 23.4 300 02/15/97 Centaur
1997 XF11 0.74 2.14 4.1 2 12/06/97 Apollo
1998 KY26 0.98 1.48 1.5 0.025 05/28/98 Apollo
1998 SG36 6.0 11.1 15.2 30 09/13/98 Centaur
1998 OX4 0.81 2.3 4.5 0.23 07/26/98 Apollo; Small impact probability.
1999 TD10 12.3 191 6.0 84 10/03/99 Scattered Disk Object
2000 BF19 0.92 2.1 6.4 0.56 01/28/00 Apollo; Briefly thought to have imact probability.
2000 EC98 5.5 15.6 4.5 64 03/03/00 Centaur
Although Spacewatch routinely finds 8000 main belt asteroids
and 1-4 near-Earth asteroids (NEAs) on a monthly basis, the table above
highlights some of the more notable finds.
- October 27, 1989 - David Rabinowitz discovers the first NEA in the course
of preliminary checkout and familiarization with our Tektronix 2048x2048 CCD, (1989UP).
- First automated discovery of an NEA was (11885) 1990 SS.
- (5590) 1990 VA marked the first Aten type asteroid - whose
orbital period is less than 1 year - discovered by Spacewatch.
- Spacewatch discovered its first "Very Fast Moving Object"
(VFMO) which was a 5-10 meter oject which passed by the Earth with barely
170,000 km to spare during Gulf War (1991 BA).
- On 1991 November 6, 1991 VG, an Arjuna object was
discovered. It was recovered in April of the following year at a magnitude
of 22. We define an Arjuna type asteroid as one with a nearly
Earth-like orbit.
- (5145) Pholus (1992 AD) has a perihelion just inside
Saturn's orbit and aphelion outside Neptune's. Pholus was the second of
the Centaurs discovered and eight additional ones have been discovered
since by Spacewatch. The second Centaur found by Spacewatch was recently
numbered and named as (7066) Nessus (1993 HA2). Centaur
1995 SN55 is the intrinsically brightest Centaur yet
discovered, brighter even than Chiron, the first Centaur ever discovered. The
orbits of these bodies are unstable and easily perturbed while passing by the
giant planets. Consequently the possibility exists for them to be either
ejected from the solar system or nudged towards the inner planets in the
future. They may be the direct progenitors of the short-period comets and
must be fed from a source region such as the Edgeworth-Kuiper belt or the
Oort Cloud.
- 1993 KA2 passed within 150,000 km of the Earth and
1994 XM1 came within 105,000 km - a record close approach.
- 1995 CR came close enough to be captured on video in real time
at Kitt Peak.
- 1997 XF11 is predicted to pass within 950,000 kilometers
of Earth on October 26, 2028. Early predictions suggested an approach to
within only 45,000 kilometers, but observations from 1990 were found which
allowed improved estimates and a much more generous miss distance.
- 1998 KY26 is a small object about 30 meters in
diameter which was found to have a record short rotational period of
just 10.7 minutes.
- As of April 2000 - Spacewatch has discovered 216 NEAs, 14 comets,
9 Centaurs, 7 TNOs and more than 294,000 main belt asteroids. That number grows by several thousand on average every lunation. As of the 2000 March 20 issue of the MPCs, 180 asteroids discovered by Spacewatch have been numbered thus far, including 17 NEAs, 4 Centaurs
and 5 Trojans.
Last Update: April 18, 2000
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